diff --git a/compiler/src/dotty/tools/dotc/core/SymDenotations.scala b/compiler/src/dotty/tools/dotc/core/SymDenotations.scala
index a5bf09325c29..12a1dc697cc4 100644
--- a/compiler/src/dotty/tools/dotc/core/SymDenotations.scala
+++ b/compiler/src/dotty/tools/dotc/core/SymDenotations.scala
@@ -1410,6 +1410,37 @@ object SymDenotations {
     def namedType(using Context): NamedType =
       if (isType) typeRef else termRef
 
+    /** Like typeRef, but objects in the prefix are represented by their singleton type,
+     *  this means we output `pre.O.member` rather than `pre.O$.this.member`.
+     *
+     *  This is required to avoid owner crash in ExplicitOuter.
+     *  See tests/pos/i10769.scala
+     */
+     def reachableTypeRef(using Context) =
+       TypeRef(owner.reachableThisType, symbol)
+
+    /** Like termRef, but objects in the prefix are represented by their singleton type,
+     *  this means we output `pre.O.member` rather than `pre.O$.this.member`.
+     *
+     *  This is required to avoid owner crash in ExplicitOuter.
+     *  See tests/pos/i10769.scala
+     */
+    def reachableTermRef(using Context) =
+      TermRef(owner.reachableThisType, symbol)
+
+    /** Like thisType, but objects in the type are represented by their singleton type,
+     *  this means we output `pre.O.member` rather than `pre.O$.this.member`.
+     */
+    def reachableThisType(using Context): Type =
+      if this.is(Package) then
+        symbol.thisType
+      else if this.isTerm then
+        NoPrefix
+      else if this.is(Module) then
+        TermRef(owner.reachableThisType, this.sourceModule)
+      else
+        ThisType.raw(TypeRef(owner.reachableThisType, symbol.asType))
+
     /** The variance of this type parameter or type member as a subset of
      *  {Covariant, Contravariant}
      */
diff --git a/compiler/src/dotty/tools/dotc/transform/SymUtils.scala b/compiler/src/dotty/tools/dotc/transform/SymUtils.scala
index ecea13e5b8ee..c2377467a226 100644
--- a/compiler/src/dotty/tools/dotc/transform/SymUtils.scala
+++ b/compiler/src/dotty/tools/dotc/transform/SymUtils.scala
@@ -223,9 +223,9 @@ object SymUtils:
       else owner.isLocal
     }
 
-    /** The typeRef with wildcard arguments for each type parameter */
-    def rawTypeRef(using Context) =
-      self.typeRef.appliedTo(self.typeParams.map(_ => TypeBounds.emptyPolyKind))
+    /** The reachable typeRef with wildcard arguments for each type parameter */
+    def reachableRawTypeRef(using Context) =
+      self.reachableTypeRef.appliedTo(self.typeParams.map(_ => TypeBounds.emptyPolyKind))
 
     /** Is symbol a quote operation? */
     def isQuote(using Context): Boolean =
diff --git a/compiler/src/dotty/tools/dotc/transform/SyntheticMembers.scala b/compiler/src/dotty/tools/dotc/transform/SyntheticMembers.scala
index 22841a5cf1a0..558122b52865 100644
--- a/compiler/src/dotty/tools/dotc/transform/SyntheticMembers.scala
+++ b/compiler/src/dotty/tools/dotc/transform/SyntheticMembers.scala
@@ -521,7 +521,7 @@ class SyntheticMembers(thisPhase: DenotTransformer) {
     else {
       val cases =
         for ((child, idx) <- cls.children.zipWithIndex) yield {
-          val patType = if (child.isTerm) child.termRef else child.rawTypeRef
+          val patType = if (child.isTerm) child.reachableTermRef else child.reachableRawTypeRef
           val pat = Typed(untpd.Ident(nme.WILDCARD).withType(patType), TypeTree(patType))
           CaseDef(pat, EmptyTree, Literal(Constant(idx)))
         }
@@ -563,7 +563,7 @@ class SyntheticMembers(thisPhase: DenotTransformer) {
       if (existing.exists && !existing.is(Deferred)) existing
       else {
         val monoType =
-          newSymbol(clazz, tpnme.MirroredMonoType, Synthetic, TypeAlias(linked.rawTypeRef), coord = clazz.coord)
+          newSymbol(clazz, tpnme.MirroredMonoType, Synthetic, TypeAlias(linked.reachableRawTypeRef), coord = clazz.coord)
         newBody = newBody :+ TypeDef(monoType).withSpan(ctx.owner.span.focus)
         monoType.entered
       }
diff --git a/tests/pos/i10769.scala b/tests/pos/i10769.scala
new file mode 100644
index 000000000000..5c63d2c807d0
--- /dev/null
+++ b/tests/pos/i10769.scala
@@ -0,0 +1,16 @@
+package stm
+
+trait STMLike[F[_]] {
+  import Internals._
+
+  sealed abstract class Txn[+A] {}
+
+  object Txn {
+    def abort[A](e: Throwable): Txn[A] = Abort(e)
+  }
+
+  object Internals {
+    case class Abort(error: Throwable) extends Txn[Nothing]
+    case object Noop extends Txn[Nothing]
+  }
+}
diff --git a/tests/pos/i10769b.scala b/tests/pos/i10769b.scala
new file mode 100644
index 000000000000..2e097460b5bf
--- /dev/null
+++ b/tests/pos/i10769b.scala
@@ -0,0 +1,21 @@
+package stm
+
+trait STMLike[F[_]] {
+  import Internals._
+
+  sealed abstract class Txn[+A] {}
+
+  object Txn {
+    def abort[A](e: Throwable): Txn[A] = Abort(e)
+  }
+
+  object Internals {
+    case class Abort(error: Throwable) extends Txn[Nothing]
+    case object Noop extends Txn[Nothing]
+  }
+
+  class Foo {
+    case class Abort(error: Throwable) extends Txn[Nothing]
+    case object Noop extends Txn[Nothing]
+  }
+}